AMERICAN INSTITUTE. 389 



success ; use of alkaline salts, sulphates, phosphates, nitrates, 

 chlorhydrates of pot-ash, soda and ammonia, no success; earthy 

 salts, carbonates and sulphates of lime, of magnesia, no success ; 

 milk of lime, feeble action; metallic salts, sulphate of iron and of 

 copper, pretty good results ; black soap, the Ridolfi plan, pretty 

 good results; sulphur, the Kyle & Gontiplan, success; monosul- 

 phurate of potassium, no success ; monosulphurate of calcium, a 

 similar action ; polysulphurate of potassium or lime of sulphur, 

 half success; polysulphurate of calcium, Grison plan, success. 



The treatment of the vines with sulphur or sulphurates before 

 buds are out has no effect. But after that giving them a wash- 

 ing with it three or four times, has destroyed the disease. 



Mr. Schmitt, horticulturist, Lyons, sends petunia seeds, flowers 

 of which are of variegated color and very double. 



You are greatly concerned to find a succedaneum for our pre- 

 cious potato. If Mr. Remont can succed in giving us the diosco- 

 rea batatas for a general crop, he will do a public good which will 

 forever make his name great. 



GLASS FOR HOT BEDS, CONSERVATORIES, &c. 



Experience has taught us that we cannot pay too much atten- 

 tion to glass for such purposes, or to the frames for it. About 

 forty per cent of the solar light which falls on the purest crystal 

 is reflected from it and never l^asses through it; and we may 

 readily infer that three-fourths of the light which falls on green 

 or impure glass never passes through.it. Large squares of glass 

 burn plants much more than the small ones. The worse the glass 

 the more necessity for careful ventilation. The English make 

 better glass for these purposes than we do. The squares of glass 

 at Hatley, are three millimetres, (one-eighth and a quarter of an 

 inch) thick, and are marked with fine parallel rays. Mr. Lindley, 

 (of the Vegetable Kingdom,) recommends these much; they dis- 

 perse the light without loss of transparency, and thus render 

 shading it unnecessary when the sun shines ardently. Much is 

 said as to the best color for such glass. The learned Mr. R. Hunt, 

 decided on a pale yellowish green, produced by using a little 

 oxide of copper in making the glass. That it is very advantageous 

 to the plants. 



LIGHTNING. 



Pliny thought that there were three sorts of lightning — one 

 dry and the other humid. The first struck and scattered wood, 

 &c., without setting it on fire; the humid blackened and smoked. 

 The third which they called the c/ear, was deemed a prodigy ; it 



[Am. Inst.] S6 



